1. Field of the Invention
This invention pertains generally to the field of mechanical guns and projectors, and more particularly to fluid pressure propulsion, with control for discharge of fluid pressure provided by a valve. In a preferred embodiment, the present invention is manifested in a single-axis bolt and valve assembly used within a paintball marker.
2. Description of the Related Art
Fluid pressure propulsion has been used in combination with various types of guns and projectors for many years. As an alternative to gun powder and other explosive substances, various pump guns existed which allowed an operator to pump air into a chamber until sufficient fluid was compressed to attain the necessary pressure to reasonably fire a projectile. Many BB and pellet guns were sold for many years that utilized this technology. These guns, while fully functional and capable of firing projectiles at great speeds, suffered from many significant drawbacks. Foremost among these was the inability to keep the gun in a ready-to-fire state, commonly due to slow leakage through the pumping mechanisms, and the delay time between firing successive shots, necessitated by the need to pump another charge of air into the pressure chamber after each shot. In addition, having been designed to resemble the gun powder versions, they were often rather large and heavy. While weight reduces recoil in gun powder versions, it is of lesser importance in the less powerful pump guns.
As an alternative to and improvement over the pump-pressure guns, various gas and liquified gas cylinders were provided to deliver a steady source of fluid pressure to the gun. Exemplary of these were the CO2 cartridges which were small and lightweight, but which provided a very limited number of successive firings before requiring replacement. To fire these guns, various mechanical triggering devices were used to control the actuation of a valve. Common valves required a substantial amount of time to activate and reset, which in view of the relatively small number of shots available was not normally considered a limitation for these guns.
A number of years ago, a new gun was developed which would fire small capsules or balls of paint that were frangible, and so would break relatively easily upon impact. By filling the frangible exterior shell with liquid paint, it was possible to visually determine whether a participant had been “hit”. Consequently, the guns are commonly referred to as markers, since rather than inflicting harm or death, a paintball gun marks the point of impact. The early markers made it possible to conduct relatively close-range training drills for military and civilian training, without the need for other types of complex, expensive and unreliable training weapons or the fear of serious harm that would be associated with more traditional guns.
Many developments have occurred over the years that have evolved the early paintball guns into the more modern counterparts. These developments have occurred in all aspects, affecting not only the technology of firing and propulsion, but also in areas separate and distinct from the guns, such as safety and in the formal organization of teams and competitions. In a comparatively few recent years, the development has progressed and evolved into both a science and industry of its own. As a sport, paintball has been identified as the third largest participant sport in the United States with millions of participants, has substantial numbers of participants and competitions the world over, and continues to grow in popularity both in numbers of participants and in spectators.
One area of development which has and continues to be very challenging to gun designers is the firing rate of a gun. To be most effective, a modern paintball gun will preferably be capable of firing paint balls at rates not measured in balls per second, but instead in the tens of balls per second. More rapid firing rates permit the balls to be distributed through lesser angles of an arc, in the event the gun is being moved while being fired. Since movement and motion are inseparable from paintball, the higher firing rate translates into a greater likelihood of marking an opponent. This can be readily contrasted with the pneumatic guns outside of the paintball industry, where firing rates are more commonly measured in seconds per shot or in only a few shots per second.
Another demanding area of development is the size and weight of the gun. While size and weight are often interrelated in most products since a larger product of otherwise identical construction will weigh more, in the case of a paintball gun the size and weight bring about different benefits and so are somewhat independent. With regard to weight, the gun must be held and moved about. At times, such as when surprised by an opponent, the gun will most desirably redirected in as little time as possible. Lower weight guns can be moved about more quickly, and may further be aimed in less time. With regard to size, the gun will sometimes be held out beyond the shelter of a barrier, exposing only the gun and not the person. The smaller a gun, the more difficult it will be to be marked by an opponent.
Additional areas that have required much consideration and development have included the reliability of successfully firing the gun, and the ease of cleaning out the gun when a paint ball is broken within the gun. When a paint ball breaks within the gun, a way must be provided to remove the components since paint will be smeared or splashed about inside the gun, and without cleaning, will increasingly interfere with proper operation. The more readily the components along the path of the ball are removed, the easier and quicker it will be for a participant to recover from a broken ball. Nevertheless, the precision of components and operation must still be maintained, or there will be many more balls breaking.